Machine for forming piston ring spacer-expanders from strip stock

ABSTRACT

A machine for making spacer-expanders for piston oil rings of the type described in U.S. Pat. No. 3,477,732. The machine comprises a punch press having a plurality of stations through which strip stock is fed progressively in accurately predetermined increments, the strip stock being worked between dies at each station to transform the strip stock into completed rings. The press includes one or more punching stations where the strip stock is pierced and blanked, one or more forming stations where the pierced and notched strip is bent to form the spring legs of the spacer-expander and then curled into a channel-shaped cross section, a coiling station where the channel-shaped stock is fashioned into a coil, and a cutoff station where each coil is sheared from the strip to form the semifinished ring. The press also includes a special transfer apparatus for transferring the semifinished ring to a final work station wherein the end joints are trimmed and formed to final configuration, after which the finished rings are loaded automatically in stacked relation on a cylindrical mandrel.

United States Patent Overway [4 1 Mar. 7, 1972 STRIP STOCK [72] Inventor: Roy E. Overway, Grand Haven, Mich.

[73] Assignee: Sealed Power Corporation, Muskegon,

Mich.

[22] Filed: May 21, 1970 [21] Appl. No.: 39,498

[52] US. CL ..72/326, 72/332, 72/420 [51] Int. Cl. ..B2ld3ll00, B21d 28/00, B21j 13/10 [58] Field of Search ..72/420, 332, 326

[56] References Cited UNITED STATES PATENTS 2,697,865 12/1954 Norton ..72/324 X 2,591,483 4/1952 West ..72/338 X Assistant Examiner-R. M. Rogers AttorneyBames, Kisselle, Raisch & Choate [5 7] ABSTRACT A machine for making spacenexpanders for piston oil rings of the type described in US. Pat. No. 3,477,732. The machine comprises a punch press having a plurality of stations through which strip stock is fed progressively in accurately predetermined increments, the strip stock being worked between dies at each station to transform the strip stock into completed rings. The press includes one or more punching stations where the strip stock is pierced and blanked, one or more forming stations where the pierced and notched strip is bent to form the spring legs of the spacer-expander and then curled into a channel-shaped cross section, a coiling station where the channel-shaped stock is fashioned into a coil, and a cutoff station where each coil is sheared from the strip to form the semifinished ring. The press also includes a special transfer apparatus for transferring the semifinished ring to a final work station wherein the end joints are trimmed and formed to final configuration, after which the finished rings are loaded automatically in stacked relation on a cylindrical mandrel.

Primary Examiner-Charles W. Lanham 12 Claims, 53 Drawing Figures /50 2 4 I06 no //8 /8 I50 H6 He H6 6 208 a *3 888 @{2 :51!" 0 a 0 I 750 1 T 204 202 2o 54 ion I itagaan IStggOn I Station Skggon st ogon '46 fi on a 2/4 Punchfluts 51cm Leqs [De Eat i Band I M 1- 7 Trim & Be d l & Jolnt t2 Jung Lgqs Ifi ga 5 I End Tabs" PAIENTEDMAR 7 I912 SHEET 03 0F 17 N rm mh \k\%b vmw HI m WA INVENTOR.

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ATTORNEYS PATENTED MR 7 I972 SHEET 1SUF 17 sci rllllll ATTOR NE Y5 MACHINE FOR FORMING PISTON RING SPACER- EXPANDERS FROM STRIP STOCK This invention relates generally to a punch press and particularly to an apparatus for punching metal in the form of a strip and forming such punched strip into rings.

More specifically, the invention relates to an apparatus for progressively forming in a continuous operation a flat ribbon metal strip into spacer-expander spring rings of the type commonly located between thin metallic rails in the oil groove of a piston of an internal combustion engine.

An object of this invention is to enable production of such rings accurately, economically and at a high rate.

Another object is to provide an improved machine capable of automatically forming spacer-expanders of the type disclosed in US Pat. No. 3,477,732, particularly in connection with FIGS. 1-5 inclusive and FIGS. 15 and 16 thereof.

A further object is to provide an improved machine capable of performing the improved method of making such a spacerexpander as disclosed in a copending application of Frank G. Warrick, Ser. No. 39,264, filed May 2, 1970, titled Method of Forming a Spacer-Expander, and assigned to the assignee of the present application.

A further object is to provide an improved machine of the above character utilizing certain components and functions of the machine disclosed and claimed in US. Pat. No. 2,925,847, assigned to the assignee of the present application, and to improve upon said prior machine.

Other objects, features and advantages of the apparatus of this invention will become apparent from the following detailed description and accompanying drawings wherein:

FIG. 1 is a fragmentary front elevational view of an exemplary but preferred embodiment of the machine of the present invention.

FIGS. 2, 3, and 4 are fragmentary plan views of the strip stock respectively showing the operations performed thereon at the first, second and third punching, blanking and bending stations of the machine.

FIG. 5 is a fragmentary perspective view of the strip stock illustrating the feed and leg bending operations performed thereon successively at stations Nos. 3 and 4 respectively.

FIG. 6 is a fragmentary view partially in vertical elevation and partially in vertical center section through the strip guide infeeding mechanism and leg-bending dies of station No. 4.

FIGS. 7 and 8 are fragmentary end elevational and part vertical sectional views taken generally on the line 7 7 of FIG. 6 and respectively illustrating the dies of station No. 4 in their open and closed positions.

FIG. 9 is a fragmentary plan view of the strip infeed guide of station No. 4.

FIGS. 10 and 11 are fragmentary enlarged views of the dies as viewed in FIGS. 7 and 8 respectively.

FIG. 12 is a fragmentary front elevational view showing a portion of the die structure shown in FIG. 6 but enlarged thereover and with the dies in closed position.

FIG. 13 is a vertical sectional view taken on the line 13-13 of FIG. 5 but enlarged thereover.

FIG. 14 is a fragmentary front elevational view of the dies of station N o. 5 shown partially in vertical center section and with the dies closed.

FIG. 15 is a fragmentary end elevational view of the entrance to station No. 5 taken on the line 15-15 of FIG. 14.

FIG. 16 is a fragmentary vertical sectional view taken on the line 16-16 of FIG. 21 and illustrating the progressive strut bending operation being simultaneously performed by the last seven of the 10 punches and associated dies of station No. 5.

FIGS. l7, 18, 19, 20, and 21 are fragmentary vertical sectional views taken respectively on the line 17-17 of FIG. 14 and lines 18-18, 19-19, 20-20 and 21-21 of FIG. 16.

FIG. 22 is a vertical sectional view taken on the line 22-22 of FIG. 16 illustrating the finished cross-sectional contour of the strip as it emerges from station No. 5.

FIG. 23 is a fragmentary horizontal sectional view taken on the line 23-23 of FIG. 14 illustrating the stationary stripper components in the lower die shoe of station No. 5.

FIG. 24 is a fragmentary horizontal plan view of a portion of the structure shown in FIG. 23 with the stationary stripper parts removed to better illustrate the underlying movable stripper and stationary forming dies in the lower die shoe.

FIGS. 25, 26, and 27 are fragmentary vertical sectional views taken respectively on the lines'25-25, 26-26 and 27- 27 of FIG. 14.

FIG. 28 is a fragmentary perspective view of the left-hand stripper plate of station No. 5 shown by itself.

FIG. 29 is a fragmentary front elevational view of a portion of the induction heating coil of station'No. 6 and also illustrating the coiling and cutoff apparatus of station No. 7 of the machine.

FIG. 30 is a fragmentary front elevational view of the components of station No. 7 with the guide shield and blowoff air tube parts removed to better illustrate details.

FIG. 31 is a fragmentary end elevational view of the entrance guide of station No. 7 looking in the direction of arrow 31 in FIG. 30.

FIG. 32 is a fragmentary vertical sectional view taken on the line 32-32 of FIG. 30.

FIG. 33 is a fragmentary vertical sectional view taken on the line 33-33 of FIG. 30.

FIG. 34 is a fragmentary plan view of the strip stock after it has been severed in the cutoff operation of station No. 7.

FIG. 35 is a fragmentary front elevational view of a portion of station No. 7 illustrating the strip coiling anvil and associated bending pad in the open position thereof.

FIG. 36 is a fragmentary end elevational view of actuating linkage in station No. 7 as viewed on the line 36-36 of FIG. 30.

FIG. 37 is a fragmentary front elevational view of the apparatus of stations Nos. 8 and 9 of the machine.

FIG. 38 is a fragmentary front elevational view of a portion of the station No. 8 apparatus shown in FIG. 37 but illustrating the pusher members in closed position embracing the entrance cone of this station.

FIG. 39 is a side elevational view of the apparatus of station Nos. 8 and 9.

FIG. 40 is a fragmentary horizontal sectional view taken on the line 40-40 of FIG. 37 illustrating a portion of the apparatus of station No. 9.

FIG. 41 is a horizontal sectional view taken on the line 41- 41 of FIG. 37.

FIG. 42 is a horizontal sectional view taken on the line 42- 42 of FIG. 37.

FIG. 43 is a fragmentary horizontal section of the shot pin and slide parts of FIG. 42 but with the shot pin shown in engaged position with the slide.

FIG. 44 is a fragmentary side elevational view illustrating the punch, clamp, and die components of station No. 8, FIG. 44 being partially taken in vertical center section and enlarged over FIG. 39.

FIG. 45 is a fragmentary vertical sectional view taken on the line 45-45 of FIG. 44.

FIG. 46 is a fragmentary horizontal sectional view taken on the line 46-46 of FIG. 44 but greatly enlarged thereover.

FIG. 47 is a fragmentary vertical sectional view taken on the line 47-47 of FIG. 46.

FIG. 48 is a fragmentary plan view of a portion of the parts shown in FIG. 46 but with their position changed to illustrate the joint trimming and initial bending action.

FIG. 49 is a view similar to FIG. 48 showing the parts at the completion of the trim and bending stroke.

FIG. 50 is a fragmentary side elevational view of the lefthand clamp member shown in FIGS. 46, 48, and 49.

FIG. 51 is a fragmentary side elevational view of the righthand shearing and bending punch shown in FIGS. 46, 48, and 49 FIG. 52 is an end elevational view of the left-hand forming die shown in FIGS. 46, 48, and 49.

FIG. 53 is a fragmentary perspective view of one end of the spacer-expander illustrating the end joints thereof after being trimmed and bent in station No.8.

For purposes of facilitating description and not by way of limitation, the machine 100 of the present invention is illustrated with the proper dies for forming the piston ring spacerexpander illustrated in the aforementioned Warrick US. Pat. No. 3,477,732, particularly the spacer-expander 58 shown and described in conjunction with FIGS. l-5 inclusive thereof and with the end joint construction shown and described in conjunction with FIGS. 14-16 inclusive thereof, this patent being incorporated herein by reference and hence spacer-expander 58 thereof not being described herein.

GENERAL ARRANGEMENT Machine 100 of the present invention is shown substantially in its entirety in FIG. 1 and generally consists of a punch press similar in part to that shown, described and claimed in the aforementioned Burns et al. U.S. Pat. No. 2,925,847, which is incorporated herein by reference for a detailed disclosure of certain portions of the machine identified in more detail hereinafter. Machine 100 has a base 102 which supports a frame'104 and a motor 106 on frame 104 which drives a flywheel 108 through a belt 110. Flywheel 108 is connected by a clutch 112 with the crankshaft 114 of the press.'Clutch 112 is of the positive drive, electric throwout type. Shaft 114 is journaled on the frame of the machine in bearings 116. A pair of magnetic brakes 118 are arranged around shaft 114 and when electrically energized operate to seize shaft 114 when the circuit to the brake is closed. Shaft 114 has three crank portions to which the upper ends of connecting rods 120, 122,

. and 124 are individually pivotally connected. Rods 120, 122,

and 124 are connected respectively at their lower ends to associated rams 126, 128, and 130 which are guided for vertical reciprocating movement on frame 104 in ways formed in three sets of guide plates 132, 133, and 134 respectively.

As set forth in more detail hereinafter, ram 126 operates a piercing die assembly 136 of station No. l and a blanking and notching die assembly 138 of the station No. 2. Ram 128 operates a foot-bending and joint-notching die assembly 140 of station No. 3 and a leg-bending die assembly 142 of station No. 4. Ram 130 operates a strut bending and strip-curling die assembly'144 of station No. 5 and, also, through a linkage 804, operates a coiling and cutofi die assembly 146 of station No. 7. The end joint trimming and bending die assembly 148 of station No. 8 is powered by pneumatic rams synchronized with the operation of the press by a suitable counting and control mechanism as described in more detail hereinafter.

The end of shaft 114 remote from flywheel 108 carries a disk 150 to which a link 152 is eccentrically connected for driving a strip feeder 154 through a bellcrank 156. A suitable commercially available magnetic pickup assembly 160 is provided for counting revolutions of shaft 114 to develop one signal per each vertical reciprocation of the rams 126, 128, and 130 through their simultaneous mechanically synchronized working strokes. Pickup 160 has a rotating part 162 secured to shaft 114 for rotation therewith and a stationa ry part 164 secured to the stationary structure of the end bearing 116. Pickup 160 provides the input signal to a suitable counter control (not shown), such as that sold under the trademark Dynapar made by the Louis Allis Division of Litton Industries at the Digital Center in Gurnee, Illinois and identified as a Digital Process Controller Type 5X2-58-X-l. This controller operates through the signals derived from pickup 160 to initiate the cutoff operation as well as the air blast at station No. 7. This occurs in response to an output signal developed by storing the number of counts in the digital memory of the controller corresponding to the number of increments of advance of the strip 170 being worked in machine 100 required to pass a given length spacer-expander through the coiling die of station No. 7.' Also, this control further provides an output signal for actuating the pusher fingers of station No. 8 after allowing a time delay (corresponding to a given number of counts) for the severed spacer-expander to drop onto the nose cone of station No. 8. The remaining moknell more detail hereinafter.

The counter control is also adapted to generate a control signal for causing a transverse shuttle motion of die assemblies 136, 138, and of station Nos. 1, 2, and 3 as an end joint zone of the strip stock being fed therethrough comes into successive registry with the respective die assemblies, as set forth in more detail hereinafter.

In general, the operation of machine 100 is as follows:

Steel strip material 170, preferably stainless steel of the A.I.S.I. 301 type, is pulled from a coil 172 by feeder 154 and pushed with an intermittent advance and then pulled back to locate it stationarily at station No. 1 where the punching die assembly 136 forms the six transverse slots 174, 176, 178, 180, 182, and 184 shown in FIG. 2 per each working stroke after each incremental advance of the strip. These slots are spaced equally lengthwise of the strip and form a continuous row running the length of strip required to form a single spacer-expander 58 except for the end joint portions 186 of strip 170 located between each spacer-expander wherein the end joint tabs 275 are to be formed. In this area 186 two shorter longitudinally aligned transverse slots 188 and 190 (FIG. 2) are punched in the space otherwise taken by the fourth slot 180. The two separate punching operations performed at station No. l are obtained by providing two sets of piercing punch and die means arranged in tandem in a shuttle die assembly movable perpendicularly to the direction of strip feed in the manner set forth in the aforementioned Burns et al. US Pat. No. 2,925,847 relative to the piercing die assembly 84 described therein.

Strip 170 then advances to station No. 2 where a portion of the strip defined between slots 174 and 176 is blanked out and the portion of the next strip between slots 176 and 178 diagonally offset from the first blanking is also blanked out, to thereby define in the plane of strip 170 the material from which spring legs 76 and 78 are subsequently bent. This blanking is performed by a first die set of die assembly 138 which contains four punches to simultaneously form in one stroke of the punch two legs 76 and two legs 78 in two adjacent pitch lengths (identified as 2? in FIG. 3) in keeping with the twopitch increments of strip advance imparted by feeder 154. As in station No. 1, station No. 2 contains two die sets in 'a tandem shuttle arrangement to perform the leg blanking operation and then a first notching operation in joint area 186 when this area comes into registry with the second station (see FIG. 3).

The strip then advances through station 3 wherein die assembly 140, also a dual-tandem shuttle die assembly, bends up the feet 82 and 84 on legs 76 and 78 respectively (see FIG. 4). When the joint area 186 comes into registry with station No. 3, the rear die set performs a notching operation to form the two crossbars 281, one for the endjoint tab 275 for trailing end of one spacer-expander and the other for tab 275 for the leading end of the successively adjacent spacer-expander. These two spacer-expander lengths remain joined by a median strip 192 (FIG. 4).

The strip then advances through station 4 wherein legs 76 i and 78 are bent upwardly from the plane of the strip (FIG. 5).

Thereafter, the strip advances through station No. 5 wherein struts 74 are bent progressively by a row of punches of the punch and die assembly 144, the strip being simultaneously curled to bring the marginal bands 70 and 72 towards one another to thereby form the channel-shaped configuration of the strip (FIG. 22). The strip material then passes through the induction heater of station No. 6 to station No. 7 where the strip is coiled into a circular configuration and then cut off in the joint area.

The severed spacer-expander ring then is transferred to station No. 8 wherein die assembly 148 trims off the flash remaining on the joint tab and bends the tabs 275 to their final position. At the last station No. 9, the completed spacer-ex- 

1. In a machine for performing an operation on the parted ends of a ring segment, the combination comprising guide means including a generally cylindrical guide tube extending axially through a work station of said machine, an entrance cone disposed upstream of said work station having a leading end smaller in diameter than the free-state diameter of said ring segment and a trailing end fairing into one end of said guide tube, means for transferring a ring segment endwise onto said nose cone, pusher means for slidably embracing said nose cone and pushing said ring segment axially slidably therealong and onto and along said guide tube to said work station, shelf means movable transversely of said guide tube at said work station between a closed position adjacent to the tube and an open position spaced from the tube, said shelf means being adapted in closed position to support said ring with its axis parallel to the tube, and positioning finger means adapted to embrace the outer periphery of said ring segment in the vicinity of the parted ends thereof to contract said ring segment against said guide to thereby position said parted ends at said work station.
 2. The combination as set forth in claim 1 including punch and die means operable upon said parted ends at said work station including a movable member disposed within said tube and operable through an opening in the side thereof and a second movable member disposed outside said tube and cooperable with said first member to perform said operation on said parted ends of said ring.
 3. The combination as set forth in claim 1 wherein said pusher means is movable past said work station through the space between said shelves of said guide in the open position of said shelves to thereby remove said ring segment from said work station after the operation has been performed on said parted ends thereof.
 4. The combination as set forth in claim 3 including a guide expander removably mounted on said guide means and extending in the direction of travel of the ring segment adjacent the outer periphery of said nose cone and said tube and past said work station, said expander having a profile matching that of said outer periphery and being spaced radially outwardly therefrom a distance correlated with the free-state diameter of the ring segment being worked in said machine to thereby maintain the parted ends of the ring segment in an open condition but allowing the same to be closed toward the final position of said parted ends at said work station.
 5. The combination as set forth in claim 1 wherein said shelf means comprises first and second shelves disposed on opposite sides of said guide tube and said positioning finger means comprise a first actuator mounted on said first shelf for movement therewith and including a plunger extending toward said guide tube, an arcuate finger pivotally mounted to the free end of said plunger and slidable on said first shelf, said finger having a curved leading edge conforming to the curvature of said ring segment and terminating at a rounded nose portion, yieldable biasing means for pivoting said finger to a canted position wherein said nose portion leads said leading edge into slidable engagement with said ring segment in response to movement of said plunger toward said guide tube, said second shelf having a second actuator, plunger, positioning finger and biasing means corresponding to that carried on said first shelf and operable in the same manner but in the opposite direction such that said first and second fingers engage said ring segment on opposite sides of the parted ends thereof to draw said ends toward one another in response to said plungers moving toward one another.
 6. In a press for forming the parted ends of a spacer-expander ring segment having at each end a tab projecting circumferentially from a transverse strut toward the tab of the other parted end, and wherein said tabs each have a flash portion projecting from the tip of said tab, the combination comprising die means mounted for movement radially of said ring segment from within said ring segment between a retracted open position and an extended closed position, said die means including a central shear clamp and a pair of tab bending horns flanking said shear clamp, and punch means mounted for movement exteriorly of said ring segment in opposed relation to said die means, said punch means including a pair of shearing and bending punches aligned to travel from a position spaced from to a position overlapping and adjacent the opposite sides of said shear clamp in response to closure of said punch and die means, said punch means also having a pair of side clamps aligned with said bending horns and flanking said shearing and bending punches and a central clamp aligned with said shear clamp, and means for positioning said ring ends and for operating said punch and die means in a cycle of motions whereby said die means moves to closed position, said positioning means move to bring the parted ends of said spacer-expander individually into registry with an associated one of said horns with the end struts overlying the end of the associated horns and said flash portions overlying said shear clamp, and with a portion of said ring abutting the side of the associated horn to so locate the parted ends of the spacer-expander, then said punch means closes on said die means such that said pair of clamps engage and clamp said struts against said horns and said central clamp engages and clamps said flash portions against said shear clamp, then said shearing and bending punches engage said ends to shear the same from said flash portions and then travel between said horns and shear clamp to bend said end portions radially inwardly relative to said struts.
 7. The combination as set forth in claim 6 wherein said punch means comprises a first shoe and a second shoe, means slidably suPporting said shoes for movement in the direction of opening and closing movement of said punch means, said shoes being aligned in the direction of said movement with said first shoe closest to said die means, means forming a lost-motion connection between said shoes and yieldably biasing said shoes to normally spaced-apart positions, said side and central clamps of said punch means being mounted in said first shoe and projecting therefrom toward the associated horns and shear clamp of said die means, said shearing and bending punches being mounted in said second shoe and projecting therefrom through said first shoe on opposite sides of said central clamp, the working ends of said shearing and bending punches being retracted relative to the working ends of said side and central clamps of said first shoe in the spaced-apart positions of said first and second shoes and wherein said punch and die operating means includes an actuator connected in driving relation to said second shoe to drive the same through said working cycle of said punch means.
 8. The combination as set forth in claim 7 wherein said shearing and bending punches each have a leading surface with a leading shearing edge disposed for travel closely adjacent the associated side surface of said central die shear clamp, said leading surface being inclined from said leading shearing edge at an angle relative to punch travel away from said die means and fairing into a rounded outer edge disposed to travel with a clearance adjacent the associated bending horn, said corner fairing into a side surface adapted to slide with a slight clearance along said tab after it has been trimmed and then bent in between said punch side surface and the adjacent side surface of said bending horn.
 9. The combination as set forth in claim 8 wherein said shearing and bending punches each have a coining surface extending from said side surface thereof rearwardly and outwardly toward the adjacent side surface of the associated punch clamp, said punches traveling to a final closed position wherein said coining surfaces strike the bend imparted to said end tabs to flatten and coin the same to thereby set said bent-in tabs against springback.
 10. The combination as set forth in claim 9 wherein said shearing and bending punches and said side clamps of said punch means each have forwardly projecting ears with tapered surfaces adapted to center the associated portions of said end tabs engaged thereby on the respective die means center clamp and on said bending horns as said punches and side clamps move into engagement with said tabs.
 11. The combination as set forth in claim 6 wherein said die means includes a die shoe, means for slidably supporting said die shoe for movement through said working cycle thereof, a fluid cylinder and associated plunger connected to said shoe for imparting said movement thereto, a slide block connected to said plunger, a stationary housing having a guideway in which said block slides with movement of said plunger, and shot pin means in said block and housing relatively movable transversely of the direction of travel of said block into mutually engaged positions in response to movement of said die shoe to closed position to thereby releasably lock said die shoe in closed position, said shot pins means being moved into mutually disengaged positions to release said die shoe for movement thereof to open position.
 12. The combination as set forth in claim 1 further including means for loading said ring segments in stacked relation after the same have been operated on at said work station comprising a loading tube having a leading end telescoped into the trailing end of said guide tube and sized for receiving ring segments slid axially from said guide tube onto said loading tube by said pusher means, said guide tube having a stationary shoulder at its trailing end axially aligned with the adjacent ring segment position on said loading tube, and means for reciprocating said loading tube axially toward and away from said guide tube a distance less than the overlap of said tubes but at least equal to the axial dimension of a ring segment to thereby cause said shoulder to advance segments slidably toward a trailing end of said loading tube in response to inward movement of said loading tube to thereby clear a space on the leading end thereof to receive another ring segment when said loading tube is moved away from said guide tube in the outward reciprocation of said loading tube. 